1. Field of the Invention
This invention relates generally to fertilizer mixtures of synthetic organic and inorganic materials and particularly to a formulation and method for blending and using monopotassium phosphate with very fine particulate ureaformaldehyde to form a dry homogeneous high analysis fertilizer which may be carried in liquid for application in surface and subsurface spraying and injection fertilization.
2. History of the Prior Art
The use of fertilizer blends of both organic and inorganic material has become recognized as being advantageous in many fertilizer applications. Such blends not only supply nutrients which may be immediately absorbed into the plant root system, but also provide a source of long term nutrient supply.
In order for any nutrient material to be absorbed by a plant root system, it must be dissolved to create various ion structures or salts which are readily attracted and absorbed into the root tissue by an ion exchange process. The inorganic fertilizer material which may include phosphates and potassium are soluble in water and form ions readily when dissolved. Therefore when such fertilizer is supplied to the soil in liquid form, the nutrient ions or salts are immediately available for absorption, or, if a dry inorganic fertilizer is used, the nutrient ions or salts become available as water is percolated through the soil.
Organic fertilizers, those structures which include animal, vegetable and synthetic carbon structures, on the other hand, are advantageous in that they exhibit slower rates of decomposition. That is, organic fertilizer material ordinarily is not readily soluble in water, but only breaks down by microorganism action in the soil to release nutrient ions over a period of time and thus a single fertilizer application may supply nutrients for an extended period. Such organic materials are often referred to as slow release fertilizers.
As mentioned above, organic and inorganic fertilizers may be supplied in either soluble or insoluble form and may either be spread or sprayed onto surface areas or injected or otherwise supplied to subsurface areas. However, when using readily soluble fertilizers, one is limited to the amount of nutrients which may be effectively supplied to the soil without causing damage to plant tissues, a problem commonly referred to as plant or root burn. As the nutrients of the soluble fertilizer are readily dissolved for plant absorption, an excessive amount of salt concentration due to the number of ions released adjacent the root system, may suppress the water absorption by the roots and in some extreme cases may extract moisture from the plant causing the plant to be subjected to a moisture deficiency.
Insoluble fertilizers, on the other hand, must be broken down by either chemical or biodegradable action and thus the rate of salt supply may be reduced somewhat depending upon climatic and soil conditions. Also, insoluble fertilizers having particulate material of a size to be readily blended with soluble material are not readily adaptable to the presently increasing use of pressure or hydraulic fertilizer injection techniques since the particle sizes of the insoluble material must be small enough to allow the fertilizer material to be injected through small bore nozzles.
Subsurface application of fertilizers is recognized as being a highly desirable method by which to provide for the efficient and effective feeding and caring of trees, shrubs and lawns by supplying nutrients directly to the area of the plant roots. Such application has the added advantage, over surface fertilizing, of decreasing the amount of fertilizer runoff or leaching caused by the action of surface waters. Further, pressure or hydraulic injection of fertilizers is a quick and easy method by which to apply fertilizer to subsurface areas without the extra work necessitated by more traditional drill or bore hole techniques.
All nutrient salts or ions are subject to leaching since water dissolves minute quantities of the fertilizer material and such dissolved material commonly moves with the water away from the area of the roots. However, all nutrients do not leach to the same degree. As an example, nitrate salts (which is the form of nitrogen primarily absorbed by plant roots) moves with ground water and rapidly leaches from the root zone while potassium is moderately leached and only a trace of phosphorus is lost. To obtain the joint benefit of liquid injection together with short and long term nutrient release, it is important to provide a mixture of organic and inorganic fertilizer material which, when mixed with water, forms a solution of the inorganic material and a portion of the organic material and forms a suspension of the remainder of the organic material. Normally the dry inorganic material is in granular or pellet form since such material dissolves in water and does not clog the hydraulic equipment. However, due to the necessity of utilizing an organic material which includes very fine or powdery water insoluble particles when using hydraulic injection equipment, problems have been encountered in effecting a uniform blend of dry organic and inorganic fertilizer components in the absence of a liquid medium.
Specifically, in mixing dry synthetic organic material such as ureaformaldehyde, or ureaform, as the requisite particle size is decreased, the more the material exhibits an ability to "flow" because of its low bulk density. That is, as the powdery organic particles are mixed with various inorganic materials in granular or pellet form, they tend to readily separate or settle through the mixture and thus the overall blend is not homogeneous or uniformly mixed. Various prior art methods for effectively dry blending insoluble organic material such as ureaform with soluble inorganic materials have necessitated that the insoluble particle size be approximately the same size as the soluble particles and therefore the insoluble material is not suitable for subsurface injection.
Therefore, to provide the market or consumer with a fertilizer having water soluble inorganic material with very fine particulate water insoluble organic material uniformly suspended therein which could be used for subsurface applications, it has been necessary to blend the organic and inorganic material in a solution. By wet mixing, the problem associated with dry blending was avoided. However, shipping, packaging, consumer handling and other such problems are increased due to the necessity that the fertilizer could only be available as a liquid or slurry.
Some examples of the prior art include U.S. Pat. Nos. 2,864,685 to Waters et al; 3,024,098 to Austin et al; 3,333,940 to Ridgeway; 3,479,175 to Murphy, Jr. et al; and 3,677,736 to Formaini.